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United states Department of Agriculture 

And 3tate Colleger of Agriculture Cooperating 

Department Circular 35 



*3^j5i»- 



CONTENTS 



Page 

General crop pests 3 

Cutworms 3 

Wirevvorms 4 

Blister beetles 4 

Grasshoppers 4 

Red spiders 4 

Slugs and snails 5 

Damping off 5 

Principal insects and diseases that attack gar- 
den crops 5 

Beans 5 

Pod-spot or anthracnose 5 

Blight 5 

Weevils G 

Bean-leaf beetle 

Bean aphis 7 

Beets •. 7 

Leaf-spot 7 

Flea-beetles 7 

Beet webworm 8 

Cabbage 8 

Black-rot 8 

Yellows 9 

Black-leg 

Club-root 10 

Common cabbage worm 10 

Cabbage looper 11 

Harlequin cabbage bug 11 

Plant-lice 11 

Flea-beetles 12 

Cabbage maggot 12 

Cucumbers, muskmelons, and squashes. ... 13 

Wilt 13 

Mosaic 13 

Anthracnose 14 

Downy mildew 14 

Leaf-spot 15 

Striped cucumber beetle 15 

The twelve-spotted cucumber beetle 16 

The melon aphis 16 

The common squash bug 17 

The squash- vine borer 17 

Onions IS 

Smut IS 

Onion thrips 10 

Onion maggot 19 

Peas 19 

Pod-spot 19 

Pea weevil 19 



Page 
Principal insects and diseases that attack gar- 
den crops — Continued. 

Four-spotted bean weevil and cowpea wee- 
vil 20 

Pea aphis 21 

Potato ,. 21 

Scab 21 

Early-blight 22 

Late-blight 22 

Tip burn 22 

Wilt 22 

Colorado potato beetle 23 

Blister beetles 23 

Flea-beetles 23 

Sweet potatoes 24 

Black-rot 24 

Stem-rot 24 

Foot-rot 24 

Tortoise beetles 24 

Flea-beetles 25 

Tomato 25 

Leaf-spot 25 

Wilt 25 

Blossom-end rot 25 

I'omato hornworms 25 

Tomato fruitworm 26 

Flea-beetles 26 

How to rnake fungicides and insecticides 27 

Fungicides 27 

Bordeaux mixture 27 

Formaldehyde 28 

Insecticides 28 

Lead-arsenate 28 

Other stomach poisons 29 

Nicotine sulphate 29 

Kerosene emulsion 29 

Soap sprays , 29 

Lime 29 

Flowers of sulphur 29 

How to spray 29 

Spraying and dusting tools 30 

Miscellaneous control methods 30 

Soil treatment 30 

Carbon disulphid 30 

Trap crops 31 

Insect friends 31 

Ladybird beetle 31 

Syrphus fly 31 



Contribution from the States Relations Service 
(Office of Extension Work North and West) 
A. C. True, Director 



NOV 17 1933 

UtvuilON Of O0CUKENT8 



^ DISEASES AND INSECTS OF THE HOME GARDEN 






\ 



W. W. Gilbert, Pathologist, Bureau of Plant Industry, and C. H. Popenoe, 
Assistant Entomologist, Bureau of Entomology 



FROjNI the time the seeds of garden crops are put into the ground 
until the crops are gathered, diseases and insects may appear that 
must be fought. The gardener who starts with a clean soil has done 
much to keep out insects and diseases, and thus save the trouble and 
cost of applying sprays. "Prevention is better than cure," especially 
in the home garden, which usually must be planted on the same ground 
year after year. Many diseases and insects live over winter in the soil 
and will appear on the plants again next season if they are put in the same 
place. One of the best ways to help get rid of such troubles is to plant 
each vegetable in a different part of the garden every year. 

Some of the worst garden troubles are brought in on roots of plants, 
and remain in the soil to attack the next crop, consequently in buying 
plants of any kind, one shoidd be sure they are healthy and free from 
insects. The roots should be clean and hairy, not swollen or knotty. 

In giving ways of controlling insects and diseases in the following 
pages, they are grouped under two headings, treatment and prevention. 

Treatment means the use of methods of control which may be applied 
after the diseases or insects have appeared in the garden, such as hand- 
picking of insects, or spraying for diseases and insects. 

Prevention means the use of such methods of control as will prevent 
the development of insects or diseases, or their being carried over to 
crops the next year, such as burning sick plants, the use of seed free from 
disease, treatment of seed to kill insects and diseases, or the planting 
of crops on parts of the garden free from disease. 

Injurious insects may be divided into two classes. First, those 
which ordinarily attack only one crop or crops of one kind. The large 
tomato worm, which confines its feeding to the plants of the tomato and 
potato family, is an example of this class. The second class eats nearly 
every kind of plant that grows in the garden. Cutworms, several other 
caterpillars, several kinds of leaf-beetles, flea-beetles, plant-lice, thrips, 
and blister beetles are examples of this class. 

GENERAL CROP PESTS 

CUTWORMS. — Cutworms appear in great numbers in the early spring 
and summer, and jjlants may be killed before the gardener notices their 
presence. The main injury done is the cutting off of the stems of young 
plants at the surface of the ground. One cutworm can kill many plants 
in one night. 

Treatment. — The best remedy is poisoned bait. This can be made 
for use in a small garden by thoroughly mixing 2 level tablespoonfuls 
of white arsenic or paris green into 5 pounds of dry bran. Then add 
from 4 to 6 quarts of water in which a half pint of sorghum or cheap 

3 



4 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 

molasses has been mixed. After the mash has stood for several hours, 
scatter it thinly over the garden or about the bases of the plants that 
have been set out. Put out the poison late in the day so that it Avill be 
moist during the night when the cutworms feed. Do this two or three 
times if the cutworms continue to cut the plants. 



A RSENIC and paris green are deadly poisons. Handle 
■^^ them with great care. Keep young children, live- 
stock, and chickens away from this bait. 



Cutworms can be gathered by hand. Dig into the ground around the 
plants that have been cut off and the gray smooth cutworms will usually 
be found curled up about an inch below the surface of the ground. 
Sometimes several may be found around one plant. 

WIREWO RMS.— Wire worms 
are common pests in the garden. 
They are long, slender, hard, 
brown worm-like larvse, the 
young of snapping beetles or 
"snap bugs." They attack and 
often do great damage to pota- 
toes, carrots, beets, sweet pota- 
toes, and onions. 

Prevention. — Deep midsummer 
cultivation and heavy fertilizing 
will reduce wireworm damage. 

BLISTER BEETLES. — Blister 
beetles are common farm pests 
and are very destructive to vege- 
tables, especially peas, beans, 
potatoes, and beets. They travel 
like army w^orms, and for this 
reason are sometimes called army 
beetles. They are hungry feeders, 
and often travel in lines, eating 
everything in their path. They 
are slender in form, somewhat 
soft-bodied, and of many colors. 
Some are entirely black, some 
are yellow with black stripes, 
some are gray, and others are gray spotted with black. 

Treatment. — When the beetles are first seen, spray with lead arsenate 
(see page 23). Hand-picking is somewhat dangerous unless gloves are 
worn, as the beetles may blister the tender skin. 

GRASSHOPPERS. — Grasshoppers are often troublesome to vegetables. 
Treatment. — Use the same bran mash as for cutworms (see page 3), 
adding one finely chopped orange or lemon to the water before mixing. 
RED SPIDERS. — Nearly all ^•egetables are attacked by what are 




Fig. 1. — Bean anthracnose on pod and seeds. 



DISEASES AND INSECTS OF THE HOME GARDEN 5 

commonly called red spiders. This is not a true spider, but a mite, 
and is so small that it can hardly be seen. It injures plants by sucking 
the juices, and when plants are neglected their strength is slowly lost 
and in time they die. In case of a bad attack, great numbers of the mites 
can be found on the leaves, and the webs Avhich the insects spin from 
plant to plant can be seen with the mites themselves passing rapidly 
over them and gathering in swarms. Sometimes the plants look as 
though scorched by fire. 

Treatment. — Spraying with soap and water (see page 29) or kerosene- 
soap emulsion (see page 29) is a good remedy. Another is spraying 
with flowers of sulphur mixed with water. (See page 29.) Watch 
for these pests, and spray when they first appear, as it is hard to save 
the plants after they are covered with the webs. 

SLUGS AND SNAILS. — Much harm is done by slugs — soft, slimy animals 
which look like snails without shells. They are black, gray, or brown, 
usually spotted with black, and grow to be 5 or 6 inches long. Snails 
also are sometimes troublesome. Attack is worst on young ])lants 
grown in hotbeds and cold frames. Tender garden vegetables of nearly 
all kinds are also injured by snails and slugs out of doors. 

Treatment. — The best remedy is air-slaked lime (see page 29) sprinkled 
over the plants and scattered about the garden. When the lime gets 
on the slugs, they throw off so much slime that they become weakened 
and die. Other remedies are soot, road dust, and sifted wood ashes. 
A strip of soot or wood ashes around the garden will keep the slugs away. 

Prevention. — To avoid slugs, remove all rotten wood and old struc- 
tures and keep the entire garden and yard free from rubbish of all kinds. 
DAMPING-OFF. — When seeds of tomato, cabbage or other vegetables 
are planted in small boxes in the house to raise early plants for setting 
in the garden, a disease called "damping-off " often causes much trouble. 
Small plants may suddenly fall over and die, or black dead areas may 
appear on the stems near the soil, which dwarf or kill the plants. 

Treatment. — Give the plants plenty of air and light and water moder- 
ately early in the morning. 

Prevention. — The best method of preventing damping-off and root 
troubles which may attack small plants is to treat the soil in the seed box 
with boiling Avater a few days before planting the seeds. (See page 30.) 
This Avill kill the diseases and insects present. 

PRINCIPAL INSECTS AND DISEASES THAT ATTACK 
GARDEN CROPS 

BEANS 

POD SPOT or ANTHRACNOSE.— Most gardeners recognize anthracnoso 
b}' the roundish sunken spots with reddish edges which it causes on the 
young pods (fig. 1). It also makes red spots on the stems and leaf veinc, 
and grows through the pods and causes rusty looking sores on the ripe 
seeds. The disease lives over winter on the seeds. 

Prevention. — See blight below. 

BLIGHT. — Bean blight shows on the pods first as Avater-soaked looking 
spots. These later become rust colored. On the lea\^es it causes large 



6 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 




patches to turn yellow, then brown, and 
die (fig. 2). This disease is also carried 
on the seed. 

Treatment. — There is no successful 
treatment. 

Prevention.- — The best way to avoid 
both anthracnose and blight is to plant 
only healthy, unspotted seeds in a part 
of the garden where beans were not 
grown the previous year. Save seed for 
next year from pods free from spots. 

WEEVILS. — The worst insect enemies 
of beans are weevils. Attack begins in 
the field, from eggs laid in a joint of the 
pod or an opening through which the 
egg is pushed. The eggs hatch into the 
larvae, or grubs, which grow inside the 
bean and soon after the beans are har- 
vested change to weevils and begin to 
come out (fig. 3). A second brood of the 
common bean weevil may be enough to 




Fig. 2. — Bean blight on leaf and pod. 

ruin a crop of beans 
for either human 
food or seed. Sev- 
eral broods may be 
produced in a year. 

The com m o n 
bean weevil is dull 
gray Avith reddish 
legs and is about 
one-eighth of an 
inch long. 

Treatment.— Bean 

wppvils Pinnnf hp ^^^' ^' — '^'^'^ common bean weevil: a, full-grown beetle; b, grub; 
f, pupa (sleeping stage). Greatly enlarged. The small straight 
controlled in the line between a and c shows length of a full-grown weevil. 

field. They breed in dry seed and 
it is, therefore, best to harvest the 
crop, and as soon as dry to fumi- 
gate it with carbon disulphid. 
Carbon disulphid is explosive, so 
the club leader or parents should 
supervise the use of it, as ex- 
plained on page 31. 

Prevention. — Plant only seed 
free from weevils. 

BEAN LEAF -BEETLE. — The . ^ ,, 

bean leaf-beetle (fig. 4) does / ^' \ ^ 

much injury in the Eastern I'^'^;- ■*. — The bean leaf-beetle: a, full-grown beetle; h, 
Q. ■ A t^ aU' 4-1 ] Pi'pa; c, grub. Greatly enlarged. Small straight line 

Otaies ana rroni UniO SOUtllWarcl between o and b shows length of full-grown beetle. 




DISEASES AND INSECTS OF THE HOME GARDEN 



to Louisiana. The beetles 
eat large round lioles in the 
growing leaves. They also 
feed on such wild plants as 
beggarweed or tickseed. 
The grubs feed on the roots 
and main stems just below 
the ground, their habits be- 
ing much the same as those 
of the better known cucum- 
ber beetles. 

Treatment. — Lead arsen- 
ate is the best remedj^ for 
this insect. On young beans 
it must be applied at half 
strength in order not to 
burn the plants. Direc- 
tions for mixing this poison 
are given on page 28. 

BEAN APHIS. — The bean 
aphis is a very small, black- 
ish plant-louse which does 
damage in all parts of the 
United States, being very 
troublesome in California, 
where it works on the early 
plants. 

Treatment. — Nicotine sul- 
phate (see page 29) is the 
best remedy if put on as soon 
later, if found necessary. 





Fig. 6. — The beet flea-beetle: a. beetle; b, 
pupa; c.fullgrowngrub. Greatly enlarged. 



Fig. 5. — Beet leaf showing 
the beet leaf-spot. 



as the plant-lice are first seen and again 

BEETS 

LEAF-SPOT . — In leaf-spot numerous 
small, dead spots are present on the 
leaves. These spots are roundish and 
have 8 white center and a purple edge 
(fig. 5). 

Treatment. — The trouble can be con- 
trolled by spraying with Bordeaux mix- 
ture (see page 27). Begin to spray when 
the disease appears and repeat every 10 
days until the end of the season. 

FLEA-BEETLES. — The beet flea-beetle 
(fig. G), also called the spinach flea-beetle, 
is very injurious to table beets, attacking 
them as soon as they are above the 
ground. The young, or larvae, grow on 
chickweed and pigweed, and a second 
brood attacks the beets. The young 



DEPAFiTMEXT C'lItflTLAR 35, IT. S. DEPARTMENT OF AORIC'ITLTURE 





Fig. S. — Cabbage black-rot. 
Slice across a diseased stem 
to show the black ring 
which the disease causes. 



sometimes })ecome so thick as to destroy en- 
tire rows of beets before the insects are even 
seen by the gardener. They even work down 
and bore into the crowns of the plants. 

Treaimeni. — This insect can be kept down 
readily by spraying with arsenate of lead (see 
page 28) w-hen the pest is first seen, and again 
as often as needed. 

Prevention. — Chick- 
weed and p i g w e e d 
(lamb's-quarters) are 
the natural food plants 

Fig. 7.— Beet webworm: o, moth; ^f the flea-beetle, and 
6, full-grown larva. Enlarged. should be killed in the 

early spring. Cutworms also feed on these weeds. 
BEET WEBWORM. — Several kinds of web worms 

attack beets b}- eating the leaves, which become 

webbed together on the growing plant. The worst 

of these pests is shown in figure 7. 

Treatment. — Spray with arsenate of lead, made as described on page 28. 

Prevention. — The garde n 

should be kept free from such 
weeds as pigweed, since these 
encourage M^ebworms and help 
them to spread. 

CABBAGE 

The diseases which attack 
cabbage also attack other plants 
of the cabbage family, such as 
cauliflower, brussels sprouts, 
and turnips. 

BLACK-ROT.— Cabbage plants 
attacked by the black-rot look 
sickly and do not groAV well. 
They usually have yellowed 
leaves with blackened veins. 
The inside of the stem shows 
a blackened ring (fig. 8) and 
the heads frequently rot in the 
field. Plants may be attacked 
by black-rot at any time during 
their growth. Serious losses 
often result from this disease. 

Treatment. — Thereis no treat- 
ment which will stop the dis- 
ease. Pull and burn sick plants. 

Prevention. — To prevent this 
trouble soak the seeds for 15 

-This cabbage plant is one-sided, stunted, and the . , • , i p i .• 

leaves curled because of yellows. mmutCS, JUSt bctorC plautmg.m 




Fig 9. 



DISEASES AXD INSECTS OF THE HOME GARDEN 



a solution of 1 teaspoon- 
ful of formaldehyde to 1 
quart of water. (See 
page 28.) Plant in soil 
free from black-rot. Set 
the plants in a part of 
the garden which has not 
been in cabbage or any 
other plant of the cab- 
bage family for a year or 
more. 

YELLOWS. — Yellows 
or wilt attacks the 
plants while small, and 
causes a black ring in 
the stem, like black-rot. 
The plants turn yellow- 
ish-green, but unlike 
black-rot the leaves fall 
off. Often one-sided 
leaves or plants are 
found (fig. 9). Many 
plants attacked dry up 
and die young, and very 
few sick plants form 





-Cabbage plant with large knotted roots 
caused by club root. 



Fig. 10. — Black-leg makes the cabbage stem turn black and stunts 
the entire plant. A few feeble side roots are developed 

above. 



heads. In many localities wilt is the 
most important cabbage disease and 
does a great amount of damage. 

Treatment. — None. 

Prevention. — The use of varieties 
which do not have this disease is 
the best method of prevention. If 
possible, set healthy young plants 
in a part of the garden where the 
disease has not appeared. 

BLACK-LEG. — Black-leg may at- 
tack cabbage plants while they 
are very small, often in the seed 
bed. The disease gets its name 
from the fact that the stem of 
the plant rots and turns black 
(fig. 10). It also causes dark 
spots on the leaves. These dead 
spots are later covered with tiny 
black pimples. In the early 
stages of the disease, the leaves 
often turn purple. Later the 
whole plant wilts and the tips of 



10 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 




Fig. 12. — The common cabbage worm: above, butter- 
fly; below, cabbage worm, c, and chrysalis, </. Greatly 
enlarged egg, b. 



the leaves rest on the ground. 

Treatment. — No effective treat- 
ment is known. Pull and burn 
the sick plants at once. 

Prevention. — To prevent black- 
leg, treat the seeds with formal- 
dehyde and follow the directions 
given under black-rot on page 8. 

CLUBROOT. — Clubroot makes 
the roots grow very large and 
knotty (fig. 11) and keeps the 
heads very small. Diseased 
plants look stunted and yellow 
and often wilt in the sun and fail 
to produce a crop. 

Treatment. — There is no rem- 
edy for sick plants. 

Prereniion. — The best way to 
prevent this trouble is to set out 
healthy plants grown in disease- 
free soil (see page 30) in a part 
of the garden where cabbages have not been grown. Apply air-slaked 
lime in the fall, at the rate of 40 pounds per square rod, to the soil where 
the disease was. Destroy diseased plants. Do not put them on manure 
or compost piles. 

COMMON CABBAGE WORM. — This worm and the white butterfly 
are known to most persons, but in some cases growers do not know 
that the velvety green caterpillar turns into the butterfly and that the 
butterfly lays the eggs from which the caterpillar comes (fig. 12). The 
cabbage worms begin work early in the season. After eating the outer 
leaves, they attack the tender inner leaves as they form, hiding in the 
young heads where it is hard to reach them with a spray. They make 
the cabbage heads unfit for food, 
partly by leaving them in a filthy con- 
dition. In cool weather the caterpil- 
lars often feed on the upper surface 
of the leaves, and at such times they 
are easily killed. The butterflies occur 
from March to October, and the 
worms are at work from Aj^ril to 
September, and later. 

The cabbage worm also feeds on 
cauliflower, kale, collards, turnips, 
radishes, and horse-radish. 

Treatment. — Spraying with arsen- 
ate of lead (see page 28) is the best 
remedy. Add a J^-inch cube of 
laundry soap to each pint of lead 

, . Fig. 13. — The cabbage looper: above, moth; 

arsenate spray when spraying cab- below, young looper and chrysalis. Enlarged. 




DISEASES AND INSECTS OF THE HOME GARDEN 



11 




Fig. 14. — The spinach louse, showing full-grown 
louse and young ones. Greatly enlarged. 



bage, otherwise the spray is not likely to stay on well. While the spray 
leaves a coating on the outer leaves until late in the season there is no 
danger, as the outer leaves are alwaj's removed before cooking, and what- 
ever trace of the arsenic might remain on the inner leaves is not sufficient to 
be injurious. Hand picking the 
worms will also help. 

Prevention. — The clearing 
up and burning of all such 
weeds as mustard, shepherd's 
purse, pepper grass, etc., be- 
fore planting cabbage plants 
will help keep down the num- 
ber of worms. Destroy all 
injured plants and stalks by 
burning as soon as the main 
crop is harvested. 

CABBAGE LOOPER. — The 
cabbage looper is the young, 
or worm, of a medium-sized 
gray moth (fig. 13). It is 
pale green and delicate look- 
ing when first hatched. When larger, it becomes strijjed, and gets its name 
of looper by its habit of doubling up, or looping, as it walks. It eats all 
kinds of cabbage-like plants, and sometimes peas, beets, celery, and 
lettuce, and even attacks tomato and potato. 

Treatment. — Same as for common cabbage worm. 

Preventioji. — Same as for common cabbage worm. 

HARLEQUIN CABBAGE BUG. — The harlequin cabbage bug, also called 
the calico bug, fire bug, or terrapin bug, is about half an inch long and red, 
spotted with black. It is a southern insect commonly found from Vir- 
ginia to California, but often works northward. 

Treatment. — The best spray for this pest is nicotine sulphate (see page 
29). The newly hatched young are much more easily killed than the 
harder, full-grown bugs. Hand pick the full-grown bugs and eggs early 
in the season. The eggs look like little black-banded barrels on end, and 
are placed in clusters on the under side of the leaves. 

Prevention. — Clean culture, especially in the fall, and planting trap 
crops (see page 31) of mustard or other plants of the cabbage family in 
the spring will help to prevent damage by this insect. 

PLANT-LICE. — Plant-lice of three kinds, the cabbage louse, turnip 
louse, and si^nach louse, do nuich damage to cabbage. These insects 
are very small, soft bodied, and greenish or yellowish in color (fig. 14). 
They appear early in the spring, and sometimes remain as late as 
December. 

Treatment. — The best remedy is nicotine sulphate (see page 29). 
Kerosene emulsion and soap (see page 29) are also good. Washing down 
the plants with a strong stream of water from a syringe, garden hose, or a 
sprayer, w411 often keep this pest from killing them. Treatment should 
be given the plants when the pests are first seen. 



hZ DEPARTMENT CIKCULAK So, U. S. DEPAKTMENT OF AGKICULTUKE 




>N- 



FiG. 1.5. — The seod-corn maggot: a, back view of fly; 6, side view; r, pupariiim; </, maggot. Greatly enlarged. 

Prevention. — Keep the garden clean of weeds on which plant-Hce feed, 
FLEA-BEETLES. — Flea-beetle.s attack young cabbages, radishes, and 
turnips. These are usually greenish or bluish black in color. They are a 
little larger than fleas, and have the same jumping habit. 

Treatment. — Use lead arsenate as for cabbage worms. Bordeaux mix- 
ture, as described on page 27, with two 1-inch cubes of laundry soap 
added, is an excellent spray to drive these insects off the plants. 

CABBAGE MAGGOT. — Cabbage and related crops often suffer badly from 
the attacks of the cabbage maggot which looks like the seed-corn maggot 
shown in figure 15. The parent of this maggot looks like the common 
house fly. Young plants are worst attacked, the maggots gnawing off 
the outer surface of and boring into the larger roots, eating the tender 
smaller roots and often boring into the lower part of the stalk. When 
very common, the cabbage maggot is one of the hardest pests to control. 
,— ^ Treatment. — Hand picking, although hard work, will 

prevent damage. It consists of pulling up the young 
cabbage or ctiuliflower plants, looking over the roots 
'/ for eggs and maggots, and destroying them by crushing 
7 with the hand or washing the roots in a strong solu- 
tion of soap, then replanting. Usually the plants 
show no bad effects from this treatment after two 

or three Aveeks. By 



looking closely, the 
little white eggs may 
be seen about the 
stalks of young cab- 
bages, and if the 
earth is raked away 
so as to expose the 
eggs to the sun they 
will dry up and not 
hatch. Keeping the 

soil well hilled around the plants causes more roots to grow, so that the 

plants can live even if some of the roots are eaten off. 

The u.se of scjuares or disks of tarred paper to protect the plants 

against the egg laying of the fly works well in small gardens. To make 





I'k;. 1(5. — Showing how tarred- 
paper pads are made and used 
to keep root-maggots from cab- 
bage plants. 



DISEASES AND INSECTS OF THE HOME GARDEN 



13 



the protectors, cut 3-inch 
squares of tarred build- 
ing paper, make a sHt 
from one side to the cen- 
ter, and several short slits 
like a star at the center 
(fig. 16). Place the 
square around the plant 
just before setting out 
and press the paper 
closely around the stem 
and down against the 
ground. The squares 
must fit tightly to keep 
out the fly. 

Prevention. — Destroy 
all old plants by burning 
in the fall. 




f 



Fig. 17.— Mottled 
cucumber leaf due 
to mosaic disease. 



CUCUMBERS, MUSKMELONS, AND SQUASHES 

WILT. — Small cucumber and squash plants usually wilt, dry up, and 
die very quickly when attacked by this disease. The trouble affects 
the stem, and prevents the plant from getting water. Larger plants 
may lose runners one at a time until the entire plant is dead. In northern 
regions, this trouble is usually most common in July. 

Treatment. — As the disease is carried by cucumber beetles, protect 
the plants as long as possible with cheesecloth covered cages to keep the 
beetles off (see fig. 22, p. 15) . Pull plants having the wilt at once and bury 
or burn them. Remove the cages when the plants become too large, and 
if beetles are still abundant spray with Bordeaux mixture and lead ar- 
senate (see pp. 27 and ^H) every ten days. 

MOSAIC. — Cucumber, muskmelon, and squash plants attacked by 
mosaic or white pickle disease are stunted and have wrinkled or mottled 
leaves (fig. 17). The aft'ected cucumber and squash fruits are often 

crooked and covered 
with green warts (fig. 
18), or they may be 
nearly white, and 
when badly diseased 
are not good to eat. 
Many affected musk- 
melons remain small 
and are not edible. 
Mosaic is spread from 
diseased to healthy 
plants by plant-lice 
and striped cucumber 
beetles and bypickers. 
Treatment. — The 

Fig. 18.— Warty cucumbers caused by mosaic or white pickle disease. plaUtS StlOUlCl DC kept 





Fig. 19. — Cucumber anthracnose makes large brown, dead 
spots on the leaves. 



14 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 

covered as long as possible 
with cheesecloth cages to 
keep oflF the striped beetles 
(fig. 22) . After the cages are 
taken ofiF, the plant-lice and 
beetles must be kept off by 
dusts or sprays. 

ANTHRACNOSE. —This 
disease of cucumbers is 
first indicated by roundish, 
brown, dead spots yi, to 
yi inch wide on the leaves 
(fig. 19). On the stems it 
makes sunken, brown spots 
which finally kill them. 
Rotting of ripe cucumbers 
is often caused by this dis- 
ease, and green fruits are 
sometimes attacked on the 
vines. The trouble usually 

appears the latter part of the season. With warm, moist weather, it may 

kill the vines in a few weeks. 

Treaiment. — Anthracnose may be controlled in part by spraying the 

plants every week with Bordeaux mixture (see page 27). Begin to apjjly 

the spray about the middle of July, or whenever the vines begin to run. 
Preventimi. — Do not plant 

cucumbers on soil where cu- 
cumbers or m u s k m e 1 o n s 

were grown the previous year. 
DOWNY MILDEW. — This 

disease of cucumbers and 

muskmelons first appears on 

the leaves in late summer. 

It causes small, angular, yel- 
lowish spots. In moist, 

warm weather it makes the 

leaves curl up and die in a few 

days. The oldest leaves show 

the trouble first. The disease 

is often very bad in States 

along the Atlantic Coast. 
Treat merit. — Spraying with 

Bordeaux mixture (see page 

27) will keep the plants from 

dying for two or three Aveeks 

longer than uns prayed 

plants. Begin to spray when 

the disease is first seen, or 

when the vines begin to run ^"-'" '^^- — Muskmelon Icaf-spot. Causes irregular, rusty- 

] . , ' brown dead spots on the leaves, which soon curl up and 

and repeat once a week. die. it also attacks cucumbers. 




DISEASES AND INSECTS OF THE HOME GARDEN 



15 




LEAF -SPOT. — This trouble is most serious on musknielons, but it also 
attacks cucumbers, particularly in the Western States. The leaves show 
irregular, brown, dead spots and 
on musknielons they soon curl up 
and die (fig. 20). On cucumber 
leaves it causes dead areas which 
soon fall out, leaving ragged 
holes. 

Treatment. — Spray with Bor- 
deaux mixture as for downy 
mildew. (See page 14.) 

STRIPED CUCUMBER BEETLE. 
— The striped cucumber beetle 
(fig. 21) as well as the twelve- 
spotted cucumber beetle (see 
page 16) live throughout the 
easten part of the United States. 
In other States there are several 
other kinds of beetles having about the same habits and which can be 
treated in the same way. The common form in the East is known as the 
striped cucumber beetle, sometimes called the striped bug, melon bug, 
or "cuke bug." The beetle is about yi inch long and has three black 
stripes. The worm, or larva, is slender and white with brownish ends. 
Injury is done mainly by beetles which have lived through the winter 
eating the young plants in the spring. The beetles also injure older plants 
by eating the leaves and gnawing the stems and roots. They usually 
come out in April or May. Late in the season they gather around the 
stems and leaves of cucumbers and melons, but on the first cool nights 
in the fall they hunt for shelter. In the larval stage, this insect causes 
damage to the roots. The beetles also spread diseases of cucumbers, 
squash, and melons. 

Treatment. — The simplest protection for garden use for this and other 
beetles is to cover the young plants with a cheesecloth-covered frame 



a > h 

Fig. 21. — Striped cucumber beetle: a, beetle; b, root- 
worm; c, pupa. Small line at right of beetleis natural 
length. 










Fig. 22. — Barrel hoop and cheesecloth cover for cucumber and squash plants to keep insects off. 



10 DEPARTMENT CIROTTLAR 35, TT. S. DEPARTMENT OF AORIClTLTr^RE 




Fig. 23. — Twelve-spotted cucumber beetle: a, beetle; b, egg 
c, root-worm; e, work of root-worm on corn root;/, pupa 
Small lines at right show natural size. 



made by placing the halves of a barrel hoop, as shown in figure 'ii, and 
co\ering the frame thus made with cheesecloth. A good grade of cheese- 
cloth must be used, as the beetles can easily go through a cheap mosquito- 
netting, and a material 
heavier than cheesecloth 
keeps the light from the 
plants. The lower edges of 
the cloth must be held down 
tightly to the ground by 
stones or other weights or 
the beetles will burrow 
underneath. Cheesecloth- 
covered frames of any size 
and shape desired can be 
made from four 1-inch 
square corner pieces to 
which strips of lath are 
nailed. 

Another method is to di- 
vide the hill into quarters, 
and each week plant in one 
of the quarters enough seed 
for a full hill. In this way, even though the insects attack some of the 
plants, there will be enough left to give a crop. 

Arsenate of lead (see page 28), as used for the Colorado potato beetle, 
is the most effective remedy to use against this insect. Bordeaux mixture 
with lead arsenate added (see page 28) dri^'es away the beetles and j^re- 
vents injury to the leaves so treated. 

THE TWELVE-SPOTTED CUCUMBER BEETLE. — The twelve-spotted 
cucumber beetle (fig. 23) is a little larger than the striped cucumber 
beetle. It often eats the cucumber leaves, causing much injury. The 
larva lives mainly on grasses and corn. 

Treatment. — Spraying with 
lead arsenate (see page 23) and 
treating in the same manner 
as the striped cucumber beetle 
are the best remedies for this 
insect in small gardens. 

THE MELON APHIS. — The 
melon aphis (fig. 24), com- 
monly called the melon louse, 
is very small, and greenish, or 
nearly jet black. It injures 
cucumbers and many other 
plants by sucking their juices. 
It occurs from early spring 
and summer to late autumn 

di • , X Fig. 24. — The melon aphis or louse, s 

_ early winter. In seasons ^,_ ^.^^^^ ^^^,^^^. ,, ^^^^om young; 

which favor its increase, par- d, wingless female. Much enlarged. 




howing 

c, nym 



: a and 

ph stage; 



DISEASES AND INSECTS OF THE HOME GARDEN 



17 



ticularly in summers following springs that are cool and rainy, it often 
appears in great numbers and does much damage, gathering in masses 
on the under side of the leaves of plants, and causing them to curl, 
shrivel, and lose color, and stopping the growth of the fruit. It often 
kills the plants outright. An attacked melon 
plant is shown in figure 25. The melon aphis, 
like others of its kind, gives ofi^ honeydew, a 
honey-like juice. When the aphids become very 
thick, the honeydew covers the leaves with a 
thin sticky coating on which the white skm^ ot 
the plant-lice stick, and this attra( t^ attention to 
the injury, as do also the wilt- 
ing and dying of the plants. 

Treatment. — The best rem- 
edy is spraying nicotine sul- 
phate (see page 29). 

THE COMMON SQUASH 
BUG. — Squashes, gourds, 
and ]uimpkins suffer from the 
same pests as cucumbers. If 
the plants escape the striped 
cucumber beetle and the melon 
aphis, they may be damaged by 
the squash bug (fig. 26, p. 18), 
commonly known as the stink 
bug from its disagreeable odor. 
Like the melon aphis, it feeds 
on the plant juices. 

Treatment. — Hand picking 
before the insect lays its eggs 
is of value. The eggs, which 
are shiny brown, are easily seen 
on the under side of the leaves 
and can be crushed. Cover- 
ing the plants as for beetles 
and using nicotine sulphate 
(see page 29) are helpful, but 

the full-grown bugs are hard Fig. 25.— Melon leaves curled by plant-lice. 

to kill. They may be trapped 

by placing small pieces of board, shingle, or bark on the ground near the 
plants. The insects go under these pieces of wood to hide during the 
day. The traps should be examined each morning and the bugs found 
should be killed. 

THE SQUASH-VINE BORER. — After cucumbers and melons have made 
good growth, they are sometimes attacked by the squash-vine borer (fig. 
27, p. 18), which, how^ever, is much more destructive to pumpkins and 
squashes, especially the Hubbard and summer bush varieties. This is 
the large white grub which bores through the stems, sometimes cutting 
them almost through near the roots. 




18 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 




Fig. 2G. — Tlie common squash bug: a, h, c, d, e, partly grown young; /, full- 
grown bug; g, eggs. Enlarged. 



Treatment. — When the borers attack cuciiniber.s, it is ahiiost impossible 
to kill them without killing the plants. The borers may be cut out of 
squash vines by slitting the stems of the vines lengthwise. After making 
the slit, portions of the vines should be covered. Help the plant to grow 
extra roots by covering damaged stems with earth. Keep the plants 
growing vigorously, and free from other insects and diseases. 

Prevention. — Plant early squash for a trap. Harrow the garden lightly 
in the fall, and plow deeply in the spring to keep the moths from coming 
out. The dead vines and old plants should be destroyed as soon as 

the crop is gathered. 

ONIONS 

SMUT. — S m u t 
causes the young onion 
])lants to die back. 
The dead leaves are 
covered with pimples 
full of black powder. 
The disease lives over 
winter in the soil. 

Treatment. — There 
is no successful rem- 
edy for sick plants. 

Fig. 27. — Squash-vine borer: o, moth with wings spread; b, moth Prpiipntinri Plant 

at rest; c, egg on section of vine; rf, caterpillar or grub in squash . 1 ' J l 

vine; e, chrysalis; /.chrysalis cell from ground. Enlarged one-third. OniOUS Oil lanO. WUcre 




DISEASES AND INSECTS OF THE HOME GARDEN 



19 



the disease has not occurred. If this cannot be done, sprinkle formal- 
dehyde solution (1 teaspoonful to 1 quart of water) in the drill after the 
seeds have been dropped and before covering, using 3 to 4 quarts of the 
solution to each 100 feet of row. 

ONION THRIPS. — The onion thrips is a very small insect, often incor- 
rectly called the onion louse, which causes 
the injury known as white blast, white 
blight, or silvertop. It also causes seal- 
lions or thick-necks. This insect often 
ruins entire fields of onions. It also at- 
tacks cauliflower, cabbage, cucumbers, 
melons, pumpkins, squashes, parsley, 
tomatoes, kale, turnips, and seed beets. 

Treatment. — Nicotine sulphate (see 
page 29) is used with success. 

ONION MAGGOT. — The onion maggot 
(fig. 28) is the worst northern onion pest. 
It eats into the bulb, starting decay, 
and often destroys the whole onion. The 
onion maggot is the larva of a small gray 
fly, which looks like a small house fly. 
Two or three broods may be looked for 
each year. 

Treatment. — The best remedy known 
is a poisoned bait to attract and kill the 
flies. The bait is made as follows: 

Sodium arsenate I level teaspoonful 

Water 1 gallon 

Cheap molasses 1 pint 

Dissolve the sodium arsenate in boiling 
water, and add the molasses. Since it 
is not necessary to cover the leaves, the 
bait may be put on in large drops by 
shaking from a whisk broom dipped into a 
bucket ot the poison. It should be applied when the flies are first seen. 




Fig. 28. — Young onion plant, showing 
onion maggots at worlc in tlie bulb; 
at right, plant exposed slightly, 
showing the same. 



PEAS 

POD SPOT. — This disease gets its name from the round or irregular 
dark spots which it causes on the pods. It also makes spots on the 
leaves and dark, sunken places on the stems; often there are dark spots 
on the seeds from diseased pods. The disease is carried over from one 
year to the next upon such disea.sed seed. 

Treatment. — There is no effective treatment for the growing crop. 

Prevention. — Save seeds from unspotted pods. Plant only healthy 
seeds free from spots. Plant in a different part of the garden each 
year. 

PEA WEEVIL. — Seed peas are often found with a single round hole in 
each, due to attack by the pea weevil or pea "bug." This insect is about 
^4 inch long and is thickly covered with brownish fuzz with black and 



20 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 



white markings. Often every 
pea in a pod when prepared for 
the table will be found infested 
with a weevil. In dry seed the 
hollowed out place under the 
skin in which the insect lives can 
be seen plainly. Many seeds that 
have been attacked will start to 
grow, but the plants are likely to 
be weak. Since this weevil has 
only one brood a year, it is treated 
more easily than is the bean or 
cowpea weevil. 

Prevention. — If you raise your 
own seed, keep it in a warm 
room in a tight bag or box for 
one full season before planting. 
The weevils will come out of the 
seed so kept and die. Do not 
plant seeds that have been injured by weevils. 

FOUR-SPOTTED BEAN WEEVIL AND COWPEA WEEVIL. — The four- 
spotted bean weevil and the cowpea weevil look much alike. While 
both like cowpeas as food, they also live on table beans in the South, 




Fig. 29. — Scab on potato. Unfit for planting. 




Fig. 30. — Spots of early-blight on potato leaf. 

and peas, chick-peas and, in fact, all such seeds large enough for them 
to grow in. They differ from the true pea weevil in that they have 
several })roods each year on dry seeds. 

Treatment. — Fumigate with carbon disulphid (see page 30), or if the 



/~^ARBON disulphid is explosive, and club members should 
^^ use it only under the direction of the club leader or parents. 



DISEASES AND INSECTS OF THE HOME GARDEN 



21 



seed are not to be used for 
planting, place in a shallow pan 
and bake in an oven for 5 to 
10 minutes. 

PEA APHIS. — The pea aphis 
is one of the largest of the 
j)lant-lice, being about one- 
eighth of an inch long. It is 
pea green, the same as its food 
plant. Attack begins upon 
the young vine, the lice gath- 
ering in clusters about the 
tips. Later they attack the 
stem and suck out the life of 
the plant. 

Treatment. — Nicotine sul- 
phate (see page 29) and kero- 
sene soap emulsion (see page 
29) are good remedies if used 
when the insects first begin 
to attack the plants in early 
spring. 

The plant-lice can also be 
beaten off the vines on to the 
ground. This can best be 
done with a brush of small 
twigs or a pine bough with 
the leaves left on. On a warm, 
sunny day the lice are killed by 




>et b 



the hot ground on which they fall and few, if any, ever 
the plants. 

This aphis also feeds on clover, alfalfa, field peas, and several 



Fig. 31. — Potato leaves with dead spots due to late-blight. 

>ack to 
weeds. 




Fig. 32. — Potato tuber rutted by lute blight. 



POTATO 

SCAB. — This t r o u b 1 e 
causes roughened brownish 
s])ots or scabs on the skin 
of the potatoes (fig. 29). In 
severe cases the whole po- 
tato may be covered with 
these spots. The trouble 
lives in the soil and is 
carried on the scabby po- 
tatoes. 

Treatment. — The control 
of this disease is entirely 
j)reventive. 

P r ev entiov . — Do not 
plant scabby seed. Do 



22 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 




Fig. 33. — -Tip burn of potato leaves 
due to hot, dry weather. 



not use lime, fresh stable manure, or wood 
ashes for fertilizer. Plant on new land where 
scab has not been found before. If troubled 
with the disease, soak the seed potatoes, just 
before cutting, for 15 minutes in a solution of 
1 teaspoonful formaldehyde in 1 quart of 
water (see page 28). 

EARLY-BLIGHT. — In the Northern States, 
this trouble usually comes in early July. It 
cau.ses dark, roundish spots on the leaves, 
which have ridges or rings (fig. 30). It is 
worse in moist, warm weather. 

Treatment. — Spray plants with Bordeaux 
mixture (see page 27), beginning when the 
disease is first seen. Repeat the spraying 
every 10 to 14 days in dry weather and every 7 
days in moist weather to the end of the season. 

LATE-BLIGHT. — In the Northern States, 
this disease is the cause of great losses in 
years when cool, moist weather occurs during 
August. It causes dark, irregular dead spots on 
the leaves (fig. 31) and stems, and spreads very 
fast. In favorable weather, the plants may be 
Later, it pro- 




killed in a few days 

duces a brown rotting of the tubers 

(fig. 32), which continues after the 

potatoes have been put into the 

cellar. 

Treatment. — Late-blight can be 
controlled by carefully spraying the 
plants with Bordeaux mixture (see 
page 27) the same as for early-blight. 
This disease is more serious than 
early-blight and to control it the 
plants must be kept covered all the 
time with a coating of the spray mix- 
ture, which must be put on with a 
good sprayer which gives a fine misty spray. Potatoes showing rot at 
digging time should not be put in the cellar with the good potatoes. 
For planting, select only sound potatoes, since the disease lives over 
winter in diseased potatoes. 

TIP BURN. — In dry, hot weather the tips and edges of the potato leaves 
often curl up, turn brown, and die (fig. 33) from lack of water and too 
hot sun. 

Treatment. — Spraying with Bordeaux mixture (see page 27), as for 
early-blight, will help to prevent this trouble. 

WILT. — This disease causes a yellowing and slow wilting of the 
plants and reduces the yield. The disease causes a browning of the 
stem end of the potatoes (fig. 34). 



Fig. 34. — Potato stem-end browning due to 
wilt. Not fit to plant. 



DISEASES AND INSECTS OF THE HOME GARDEN 



23 




Treatment. — There is no 
remedy for sick plants. 

Prevention. — Dis e a s e d 
seed potatoes should not 
be used, because in this 
way the troul^le is carried 
to the plants. Do not plant 
on land where the disease 
was bad the year before. 

COLORADO POTATO BEETLE. — If careful watch is not kept, this in- 
sect (fig. 33) is sure to injure the crop. The beetle and its slugs, 
the young or larva, are so well known that no description is necessary. 
Both slugs and beetles feed on the potato plants. After passing the 
winter in the ground, the beetles appear about the time the 

potatoes come up, lay their eggs on 
the under sides of the leaves, and 
start feeding. They often destroy small 
patches grown for garden purposes. 
The beetles sometimes feed also on 
eggplants and tomatoes. There are 
from one to three broods a year. 

Treatment. — Arsenate of lead is the 
best remedy. Use as described on 
page 28. 

BLISTER BEETLES.^Blister beetles 
rank next to the Colorado potato beetle 
as potato pests. They are slim, some- 
what soft-bodied insects of difTerent 
colors, sometimes striped, that feed on 
all kinds of vegetables, seeming to pre- 
fer potatoes, after which they attack 
beans, peas, beets, cabbage and other 
plants. They are sometimes called 
"old-fashioned potato bugs." 

Treatment. — Lead arsenate is the 
best remedy, mixed and put on as 
recommended on page 28. 

FLEA-BEETLES. — Small round holes 
in the leaves of the potatoes and vari- 
ous related crops, such as tomatoes 
and eggplants, show the presence of 
flea-beetles. 

Treatment. — Lead arsenate (see p. 
28) put on as a spray is the best remedy, 
especially if stirred into Bordeaux mix- 
ture. Bordeaux mixture (see p. 27) 
alone is an excellent spray to drive 
the beetles away. Spray both sides of 

Fig. 36. — Sweet potato slips showing . 

black-rot should not be set in the field. the leaVCS. 




24 DEPARTMENT CIRCULAR '^fj, U. S. DEPARTMENT OF AGRICULTURE 




Fig. 37.- 



-End of sweet potato showing black ring caused 
by stem-rot. 



SWEET POTATOES 

BLACK -ROT. — This wide- 
spread disease causes round- 
ish, black, sunken spots on 
the potatoes. Diseased shps 
in the hotbeds show black 
spots on the stems (fig. 36, p. 
23) or they may rot off and 
die soon after being set out. 
Blackrotted potatoes have a 
bitter taste when cooked. 

Treatment. — There is no ef- 
fective treatment for sick 
plants. 

Prevention. — To prevent 
black-rot, use fresh soil in 
the hotbeds. Select only 
smooth, sound potatoes for 
bedding and discard all diseased slips. Plant next year in a part of the 
garden where sweet potatoes have not been grown for several years. 

STEM-ROT. — The stem-rot occurs nearly everywhere sweet potatoes 
are grown. It is first indicated by the yellowing of the leaves, after 
which the plant gradually wilts and dies. Stems from diseased plants 
are black inside and the potatoes show a black ring (fig. 37). 
Treatment. — None. 
Prevention. — To prevent 
this disease, select seed for 
planting at digging time 
and only from healthy 
plants. If the plant stem is 
black inside, save no seed 
from that hill. For grow- 
ing slips, follow directions 
for prevention given under 
black-rot above. 

FOOT-ROT.— This dis- 
ease shows first about mid- 
summer as small brown or 
black spots on the stems fig.38. 

near the ground. These 
spots grow larger and become covered with many tiny black pimples. 
Finally they girdle the stems and the plants die. 

Treatment. — None. 

Prevention. — To prevent foot-rot, plant only healthy slips in a part 
of the garden not before in sweet potatoes. Follow directions for grow- 
ing slips given under black-rot prevention above. 

TORTOISE BEETLES.— There are several kinds of small beetles (fig. 38) 
which feed on sweet potato, and which are shaped much like turtles. 




-The golden tortoise beetle: d, beetle; 6, young. 
Greatly enlarged. 



DISEASES AND IVSEf'TS OF THE IIO\rE GARDEN 



25 



Ik^ 

^^^V 






Fig. 39. — Tomato leaf-spot 
causes many small dark 
spots on the leaves, which 
turn yellow, curl up, and 
drop off. 




They are usually golden, 
marked with black. They 
and their young eat the 
leaves. The young are pecu- 
liar, spiny grubs with long 
forked tails which they carry 
over their backs loaded with 
dirt for protection. 

Trea t men t. — The grower 
need not spray for these pests 
unless they become serious. 
Use arsenate of lead (page 

28). 

FLEA-BEETLES. — These are 
little, black, shiny beetles that 
hop about like fleas. They 
may not be seen unless looked 
for carefully. They cut long 
slits into the leaves or eat 
them full of small holes. 

Treatment. — Spray with arsenate of lead as directed on page 28. 

TOMATO 

LEAF-SPOT. — This disease causes many small dark spots with white 
centers on the tomato leaves (fig. 39). The bottom leaves are attacked 
first and soon turn yellow, curl up, and drop off. The disea.se is quite 
common and is usually first seen when the plants are about half grown. 

Treatment. — Thorough spraying with Bordeaux mixture (.see page 27) 
will hold the disease in check. Begin spraying as .soon as the plants 
are set in the garden and repeat every ten days. 

Prevention. — Grow plants in a different part of the garden each 
year. 

WILT. — In some States tomatoes are attacked by a wilt disease which 
]jre vents the plants from getting water. Plants so attacked wilt and die 
suddenly without any apparent reason. 

Treatment. — None . 

Prevention. — Destroy diseased plants. Use new land for tomatoes 
the next year. Several excellent varieties of tomatoes resistant to this 
disease have been bred by the United States Department of 
Agriculture. 

BLOSSOM-END ROT. — This disease causes large, dark, rotten spots on 
the blossom end of the green fruits (fig. 40, p. 26). 

Treatment.— V^atenng the plants during very dry weather has been 
found helpful in controlling the trouble. 

TOMATO WORMS OR HORN WORMS. —These large green caterpillars 
are also called tobacco hornworms or tobacco worms as they feed on both 



26 DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 




Fig. 40. — Tomato blossom-end rot. 



these ])lants (fig 41). They 
are the young of hirge hum- 
ming bird moth.s and have a 
wicked looking horn on the 
tail. The worms are harni- 
le.'s to persons and so need 
not be feared. There are 
two broods in a season. 
Vs hen the worms become full 
£rown they may cut all the 
leaves from the tomato plants. 
The gardener should be on 
the lookout for the first as 
well as the second brood. 

Treatinent. — Hand picking 
is the best remedy, but it 
takes sharp eyes to see the 
worms when they are not moving since they are of the same color as 
the stems on which they rest during the day. They may often be 
discovered by their voidings. When feeding they are more readily seen 
and can be easily killed. A single dose of lead arsenate (see page 28) 
will kill them. 

Tomato worms will often be found that have many little white cases 
on their backs. These are not the eggs of the caterpillar, as it does not 
lay eggs. They are cases or cocoons from which come little wasps that 
sting and kill tomato hornworms. Do not kill hornworms that are 
carrying these cases, as the wa-sps will be killed also. 

TOMATO FRUITWORM. — The tomato fruitworni (fig. 42), also called 
the corn earworm, is the cause of much trouble to tomato growers as it 
eats into the ripening fruit and destroys it. 

Treatment. — Lead arsenate (see page 28) put on two or three times 
will keep the insect partially under control. As long as sweet corn is 
nearby, the worms will let the tomatoes alone. Hand picking is good 
in small gardens. 

FLEA-BEETLES. — The 
potato Sea,- beetle fre- 
quently attacks toma- 
toes and does much 
damage. 

Treatment. — Dip the 
young plants in a lead- 
arsenate solution (3 
ounces of lead-arsenate 
paste in 1 gallon of 
water) before setting 
them out. Spraying 
with Bordeaux mixture 
(see page 27) will drive 

the beetles awa.y. Fig. 41. — Tomato homworm: a, moth; b, hornworm; c, chrysalis. 




DISEASES AND INSECTS OF THE HOME GARDEN 



27 




\j a 




Fig. 42. — Tomato fruitworm: a, full-grown moth; b, fruit worm. 

HOW TO MAKE FUNGICIDES AND INSECTICIDES 

Fungicides are materials used to kill germs or molds which cause 
plant diseases. 

Insecticides are materials used to kill insects which attack plants. 



TDECAUSE of the danger of poisoning from careless 
handling of these materials, it is desirable that the 
club leader or some adult be present when the solutions 
are made. This is especially true of lead-arsenate, paris 
green, and arsenic. 



FUNGICIDES 

BORDEAUX MIXTURE. — This is one of the best spray mixtures for 
controlling leaf diseases of garden plants. Since Bordeaux helps keep the 
diseases off the plants it is very important that it should be applied 
before they appear or as soon as they are seen. It can be bought in paste 
or dust form from seed dealers, or a better spray can be made at home, 
as follows: 

Bluestone (copper sulphate) 1 ounce 

Quicklime (stone lime) 1 ounce 

Water 3 quarts 

Dissolve the bluestone in 1>^ quarts of hot water in a wooden or earthen- 
ware pail. Slake the lime in a small quantity of water, then add enough 
more to make 1 J 2 quarts. Pour the bluestone and lime solutions together, 
straining them through a fine cheesecloth or brass wire strainer, and mix 
thoroughly. The mixture is Bordeaux. It should be made fresh each 
time used, as it is not good when old. 

Since stone lime air slakes rapidly and is then no longer good for 
Bordeaux, it is best to make up a stock solution of lime containing 1 
pound of lime to each gallon of water. This will keep a long time. 



28 DEPARTMENT CIRCULAR 35, U. «. DEPARTxMENT OF AGRICULTURE 




Fig. 43. — A small glass 
sprayer suitable for a 
small garden. 



A stock solution of bluestone can be made by dissolving 1 pound of the 
bluestone crystals in a gallon of water. A half pint of each of the.se 
stock lime and bluestone solu- 
tions will take the place of an 
ounce of lime and bluestone 
given in the formula. Dilute 
each with water as directed above 
before mixing. By adding 1 
ounce of lead-arsenate paste or 
Yi ounce of powdered lead- 
arsenate to Bordeaux, the mix- 
ture made is useful for killing 
insects as well as controlling 
diseases. 

FORMALDEHYDE. — Formalin. 
This chemical is used to make a 
solution for soaking potatoes, seeds, and soil to kill disease germs. Use 1 
teaspoonf ul to 1 quart of water or 1 ounce to 2 gallons of water. Formalde- 
hyde looks like water and causes the eyes to smart, but is not poisonous. 

INSECTICIDES 
Two kinds of insecticides are used for controlling insects, stomach 
poisons and contact poisons. 

Stomach poisons, such as lead and lime arsenate, and paris green, are 
used for all insects which injure plants by chewing the leaves or stems, 
like striped cucumber beetles and potato beetles. 

Contact poisons, such as kerosene emulsion and nicotine sulphate, 

which kill by touching 
the insects, are u.sed for 
sucking insects like 
plant lice and squash 
bugs. Stomach poisons 
are of no value for 
sucking insects. 

LEAD-ARSENATE. — 
Lead-arsenate is sold 
by most druggists and 
seedsmen both as a 
powder and as a paste. 
It is a good remedy for 
nearly all kinds of j)ests 
which eat the leaves of 
garden plants. Itisused 
either mixed with water 
as a spray or as a dry 
powder dusted on 
plants. 

HowtomaJcethe spray . 
r ,, N J • . u, . , , . —Take 1 level teaspoon- 

FlG. 44. — A compressed-air sprayer suitable for larger gardens and » i n i i i i 

small fruit trees. lul ot powdered lead- 




DISEASES AND INSECTS OF THE HOME GARDEN 29 

arsenate for each pint of water. Mix thoroughly and apply with 
sprayer. If lead-arsenate paste is used, take 2 teaspoonfuls for each 
pint of water to make a spray mixture. 

Hoiv to mix dust poison. — Where a sprayer is not available, a dust 
may be used. This is made by thoroughly mixing 1 pound of pow- 
dered lead arsenate with 3 pounds of air slaked or powdered lime. This 
mixture is put into a cheesecloth bag and dusted onto the plants by 
shaking the bag lightly over them. 

OTHER STOMACH POISONS, such as arsenate of lime and arsenate 
of zinc may also be bought from dealers. These are used like lead- 
arsenate, either in paste or powdered form. Directions for making the 
mixtures will be found on the packages. 

NICOTINE SULPHATE.— For small gardens use a teaspoonful of nico- 
tine sulphate in a gallon of water. A 1-inch cube of hard soap 
should be shaved up and thoroughly' mixed into the solution. 
Full directions for mixing are given on the covers of the packages. For 
large insects like the pea aphis, a little more nicotine sulphate than 
stated above should be used. By looking carefully at the newly sprayed 
plants, one can tell whether there is enough soap in the mixture. If the 
spray draws together in drops, more soap should be added. When 
possible, resin fish-oil soap should be used, but cheap laundry soap will 
do. If the nicotine sulphate solution has stood for any length of time, 
it should be mixed thoroughly before using. The insects themselves 
must be wet by the spray or they will not be killed. Therefore, the 
spraying should be very thorough, and should be done as soon as the 
insects are noticed. 

KEROSENE EMULSION. — Several kinds of kerosene emulsion can be 
bought in the stores already mixed, so it is hardly worth while to make 
it at home for the small garden. 

SOAP SPRAYS. — Ordinary soapsuds is a good spray mixture for plant- 
lice and leafhoppers. It should be made by dissolving a 1-inch cube 
of laundry soap or a rounded tablespoonful of whale-oil or fish-oil 
soap in a quart of hot water. This also must reach the bodies of the 
insects to kill them. This spray must not be used full strength on very 
tender plants, such as young cabbage or cauliflower in seed beds, garden 
peas, or young beans, as it will injure the leaves. Use one-half strength 
for these plants. 

LIME. — Lime is used to control cabbage clubroot, but it is liable 
to increase scab on potatoes. It acts at the same time to keep away 
certain insects such as maggots and grubs and is a good remedy for 
slugs. Air-slaked lime or hydrated lime is the best form to use. 

FLOWERS OF SULPHUR. — For the control of the red spider and for some 
other kinds of mites, sulphur may be either dusted on plants or mixed 
with water, a teaspoonful of sulphur to a quart of water, and sprayed. 

HOW TO SPRAY 

To do good work in killing insects and keeping diseases from the 
plants, spraying must be done in time. Do not wait until the plants 
ha^•e been harmed beyond help, but begin work as soon as the troul)lc 



so DEPARTMENT CIRCULAR 35, U. S. DEPARTMENT OF AGRICULTURE 

is noticed. Use good apparatus and spray carefully, since careless spray- 
ing merely wastes the mixture. Using a watering pot or whisk-broom 
is not spraying and will not save the plants. 

The spray should come from the nozzle in a mist so fine that it floats 
for some time in the air. This gives a better and finer coat of poison to 
the leaves and reaches many more insects. 

Do not use too much of the mixture on the plants. After spraying, 
the leaves should be wet, but not dripping. If it drips from the leaves, 
it is being wasted. If a compressed-air sprayer is used, pump it up tight 
and keep it so. 

It is better to spray with Bordeaux mixture before a rain, rather 
than after, if the mixture has time to dry before the rain begins. Dust 
sticks much better if put on after a rain, or when the dew is on in the 
morning. 



A LWAYS clean the sprayer well, inside and out, 
after using i1 
out in a few weeks. 



■^^ after using it. Unless this is done it may rust 



SPRAYING AND DUSTING TOOLS. — The sprays and dusts described 
may be put on in many ways. For the small garden, an atomizer sprayer 
(fig. 43) is good, but a compressed-air sprayer is better for gardens of 
medium size (fig. 44). 

In the case of the atomizer sprayer, the container for the liquid should 
be made of glass or brass, as Bordeaux mixture and other materials eat 
tin and iron. These sprayers cost from 50 to 75 cents. Compressed-air 
sprayers of galvanized steel may be bought for $3.50 to $5.00, and for 
$6.50 to $12.50 if made of brass. 

Dusts may be easily applied by shaking them from a fine cheesecloth 
bag or from a can with a handle with the bottom perforated with 
small holes. There are also several cheap dust guns on the market. 

MISCELLANEOUS CONTROL METHODS 

SOIL TREATMENT. — Young plants grown in flats or boxes for setting 
in the garden are often troubled with such diseases as damping-ofl[ (page 
5), and clubroot (page 10), which attack the roots and stems of the 
plants. These troubles live in the soil and the best way to get 
rid of them is to drench the soil with boiling water a few days 
before planting the seeds. Set the box of soil over the sink and pour the 
boiling water into it as fast as the soil will take it up. Use 9 quarts of 
water for a box 1 foot square with soil 4 inches deep. When the soil 
has dried out enough, plant the seeds. Seeds in this soil will sprout 
better and the plants grow faster and stronger than in diseased soil. 

CARBON DISULPHID. — Carbon disulphid is a clear yellowish liquid 
with a bad smell. It is used for treating seeds and to kill weevils and 
other insects which breed in seeds. A tin bucket or can, fitted with an 
air-tight top, makes a good fumigator. The seed should be placed in 
the bucket or can and the carbon disulphid poured onto a piece of rag 
or waste cotton and dropped upon the seed. A teaspoonful of carbon 



DISEASES AND INSECTS OF THE HOME GARDEN 



31 



disulphid is sufficient for a l-gallon can or bucket. The lid should then 
be fitted tightly onto the can or bucket and left on for 2J- hours. The 
seed should then be removed and aired. 



r^ARBON DISULPHID is a dangerous explosive 
when brought near fire. If you wish to fumigate 
with it, ask your parent or leader to show you how. 



TRAP CROPS. — Some garden insects which feed on several kinds of 
plants prefer one kind so much that they will leave the other plants and 
gather on the favorite. This habit can often be taken advantage of to 
protect garden crops. For example, a row of radishes may be planted 
next to cabbages to attract the cabbage maggot. Tomatoes and beans 
may be protected from the corn earworm by a few hills of early corn near 
the garden. A crop planted in this way to protect another by attracting 
the insect pests from it, is called a trap crop. 

INSECT FRIENDS 

LADYBIRD BEETLE. — Not all of the insects found on the garden plants 
damage the crop, as anyone will soon see who closely watches a ladybird 

beetle (fig. 45) or its peculiar 
red and bluish young when in 
a group of plant-lice. Lady- 
birds, so well known to most 
gardeners, are among the grow- 
er's best friends. One of them 
has been known to eat more 
than 80 plant lice in a day. 
Save all of these little red and 
black helpers that you can. 

SYRPHUS FLY. — Another 
friend that feeds on plant-lice 
is the curious green maggot often found among them. This is the young 
of a small yellow black-banded fly (fig. 46) that may be found about 
"lousy" plants. This is 
known as a syrphus fly 
and should be pro- 
tected. 

There are many other 
friendly insects, such 
as ground-beetles, lace- 
wing flies, and tachina 
flies. If it were not for 
these, pests would in- 
crease so fast that there 

would soon be no vege- ' ^ -.-O" ^ ^^sm^' ^ -J^ ^A~. \ ) c 
tables left to feed them. 




Fig. 45. — A ladybird: o. beetle; 6, pupa; c, young. These 
beetles and their young eat dozens of plant-lice each day. 




Fig. 46. — A syrphus fly: a, fly 
plant-lice. It is about thq 



ggot. This fly helps keep down 
of a common house fly. 



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